1. Field of the Invention
The present invention relates to a storage system, a control method for a storage system, and a storage control unit.
2. Description of the Related Art
In order to avoid the loss of data stored in a storage unit constituting a computer system when such a disaster as an earthquake occurs, a technology called “replication” is used in the recent advances of information technology. Replication is a technology for storing the replication of data, which is stored in a storage volume of a storage unit of a computer system at a main site, to a storage volume in a storage unit of a storage system at a remote site.
In the case when a computer system at a remote site detects that the computer system at the main site has shut down, a technology for the computer system at the remote site to “take over” the information processing that the computer at the main site has been executing was developed.
The information processing unit of the computer system at the main site repeatedly transmits a predetermined data called a “heart beat message” to the computer system at the remote site at intervals within a predetermined time. A technology to transmit this heart beat message using replication technology was also developed.
In this case, the computer system at the remote site detects the interruption of transmission of the heart beat message from the main site, by which the occurrence of an abnormality to the computer at the main site is detected. However, when the transmission of the heart beat message from the main site is interrupted by an abnormality of the storage unit at the main site, the computer system at the remote site cannot specify that it is the storage unit at the main site where the abnormality occurred.